The Bermuda Petrel (also known locally as the Cahow) is an amazing story of
a bird "lost" to science, and then rediscovered and brought back from near
extinction, thanks to the work of a handful of devoted individuals.
The first explorers to Bermuda noted the abundance of the species, with
total populations numbering at least several hundred thousand. The
introduction of predators (rats, cats, dogs, and pigs) and heavy hunting of
the species for food rapidly depleted populations, and by 1620, the Bermuda
Petrel was thought to be extinct. By the early 20th century,
there were tantalizing hints that the species may have survived, and in
1951, a handful (less than 20!) individuals were discovered on small rocky
islets at the mouth of Castle Harbor in Bermuda.

Dr. David Wingate began a tireless effort to restore Petrel populations,
using an approach that attempted to restore the native ecosystem on
Nonsuch Island, an island devoid of breeding Bermuda Petrels, but an
isolated and large enough island that offered the best hope for the
species in the long term. Predator control efforts on Nonsuch and
some of the surround small islets slowly began to improve breeding
conditions for Bermuda Petrel. Rats and other predators were
eliminated, and Tropicbirds, a competitor for breeding holes with the
Bermuda Petrels, were denied entrance to prime breeding locations
through the installation of precisely designed "baffles" that allowed
Petrels to enter, but restricted the slightly larger Tropicbirds from
entering nesting holes. Through ecosystem restoration and predator
control, breeding numbers slowly increased. Upon Wingate's
retirement, Jeremy Madeiros oversaw restoration efforts, including a
bold program to physically move young Bermuda Petrel chicks into nesting
holes on the restored ecosystem of Nonsuch Island. The efforts
paid off when Petrels returned to Nonsuch and began breeding there for
the first time in centuries. Total Bermuda Petrel populations are
now up to over 250 (as of 2013), and with continued management of
Nonsuch Island, the future of the Petrel is starting to look bright.

The photo above and to the right, taken by Jeremy Maderois, shows a
Cahow near an artificial nesting burrow. Note the brownish
"baffle" with the specially designed opening that covers the entrance to
the nesting burrow in the background. This is an example of the
baffles used to keep tropicbirds out of the Cahow nesting burrows.

Habitat: Pelagic outside of the breeding season,
found in the North Atlantic. Breeds on a handful of rocky islands in
Bermuda, with available nesting burrows and cavities.

Diet: From birds seen at breeding locations in
Bermuda, Bermuda petrels are known to feed on small shrimp and small squid.
Outside of the breeding season they may also feed on small fish.

Behavior: Takes food by dipping down to the
water's surface and grabbing food items with their bill.

Nesting: Nesting occurs in burrows in a few island
locations of Bermuda. They formerly nested in soil burrows,
constructed by the birds themselves, but with the effective loss of all but
a handful of nesting islands, nesting burrows are now often in limestone
crevices or artificially constructed burrows. Breeding occurs from
January through June. Bermuda Petrels are thought to nest for life,
with new nesting partners only recruited if one of the nesting pair should
perish. Only a single egg is laid each breeding season, with a very
long incubation period of about 52 days.

Song: A very vocal species, the eerie nocturnal
cries of the Bermuda Petrel led to some early explorers to declare the
islands as the "Devils' place".

Migration: After breeding season in Bermuda,
Bermuda Petrels disperse widely in the North Atlantic.

Conservation Status: Total global populations are
still very low, with populations of just a few hundred. However,
numbers are increasing through active management of their breeding islands.
The IUCN lists the
Bermuda Petrel as "Endangered", but notes that continued conservation
efforts may allow an upgrading of the status to "Threatened" at some point
in the future.